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Electric General Discussion
› An electric plank question
01-23-2007 05:06 PM  10 years agoPost 1
helidad2

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potosi mo. usa

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My son just finished an E-flite ultimate Fx bipe and while I was looking it over I noticed it has a very definate amount of upthrust . To me it looks like the motor mount which is factory installed is possibly wrong , there is not an easy way to change this as this plane has a full fuselage and the motor mount is buried in the fuse. I have been flying planks and helis a very long time and from the old school it is unheard of to have up thrust but with the new stuff I dont know . So any ideas or opinions on this .
thanks
David

even a blind hog finds an acorn now and then

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01-23-2007 05:39 PM  10 years agoPost 2
MikeC

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Mosinee, WI

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I've never had an Ultimate FX but have had many E-flite and other foamies. I can't imagine that the FX should have upthrust, level or downthrust is norm. Is this a stick mount that's glued into the fuse? If so I have usually been able to trim the end if the stick so that I can shim it to get the thrust I need.

Mike

Century Swift, TREX 450, Blade MCX, Spektrum DX7

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01-23-2007 06:35 PM  10 years agoPost 3
Rob_T

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You sometimes need up thrust on a plane with a low wing and a high engine to counteract the nose down tendancy caused by the high thrust line.

But on a bipe this is odd. Unless there is a lot of drag low down (long U/C with big wheels, no fairings and a few bracing wires etc) I would have expected a level thrust line. There is no difference due to "the new stuff" that I can think of that would explain it.

I'd test fly it before making adjustments though...

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01-23-2007 09:28 PM  10 years agoPost 4
Bdmcobra

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Manassas, Virginia

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I have the same plane. It flys straight and nice with E-flite's weird stick mount deal. Nice plane to fly slow in small areas.

fly once a day to keep the insanity away

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01-23-2007 10:36 PM  10 years agoPost 5
nappyroots2182

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Moline, il

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ive had almost every plane eflite makes. its flys great just the way it is. the upthrust is normal

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01-23-2007 10:39 PM  10 years agoPost 6
MikeC

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Mosinee, WI

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It flys straight and nice with E-flite's weird stick mount deal
Does your motor have upthrust as a result of the position of the stick mount or is it neutral?

I've thought about buying one of these. How slow can it fly? Slow enough to fly in the confines of a school gym?

Mike

Century Swift, TREX 450, Blade MCX, Spektrum DX7

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01-24-2007 05:46 AM  10 years agoPost 7
helidad2

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potosi mo. usa

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It has upthrust because the stick mount is not parrallel with the centerline of the fuselage . I called e-flite and their tech said it should not have upthrust it should be straight or zero degrees . problem is they want us to cut the wings and tail off and send it back to them we have taken pics but they want the old one and then send a new kit i understand this but a lot of time went in to building this bird and my son does not want to start over . so i think we will try to correct it by notching the wood stick and see if we can shim it to get it strait .
thanks for the replies
David

even a blind hog finds an acorn now and then

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01-24-2007 01:30 PM  10 years agoPost 8
MikeC

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Mosinee, WI

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It has upthrust because the stick mount is not parrallel with the centerline of the fuselage .
I understand that. I was directing the question to Bdmcobra. He said his flew nice and straight but did not say whether his had upthrust or not.
the upthrust is normal
Apparently not according to what helidad2 said the E-flite tech told him.

Mike

Century Swift, TREX 450, Blade MCX, Spektrum DX7

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01-30-2007 07:37 AM  10 years agoPost 9
excelpoint

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Melbourne,Australia

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I run all my planks (including my 44% Comp ARF Giles) with up and right thrust. In foamies a certain amount of up thrust really helps in hovering and harriers etc and dosnt effect straight line flight.

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01-30-2007 01:10 PM  10 years agoPost 10
MikeC

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Mosinee, WI

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In foamies a certain amount of up thrust really helps in hovering and harriers etc and dosnt effect straight line flight.
I can see how a little upthrust could help in hovering and Harriers, but no way is it not going to affect straight line flight unless there are other issues with the airframe. In most cases, especially low wing loading, flat bottom wing aircraft like Cubs, require quite a bit of down thrust to keep them from climbing like a lovesick eagle.

The only airplane I ever had that actually specified upthrust was a Multiplex Twin Star. This airplane was more than a little heavy for it's size and the upthrust basically brute forced it into the air.

Mike

Century Swift, TREX 450, Blade MCX, Spektrum DX7

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01-30-2007 04:26 PM  10 years agoPost 11
excelpoint

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Melbourne,Australia

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I agree on a non symetrical wing it would effect straiaght line. On a fully symetrical wing it dosnt. What it does do is trim an aircraft out to feel exactly the same inverted or upright(ie, the same stick pressure to hold level flight upright and inverted) also it created an aircraft that is hands off on uplines and down lines, predomintly used for aerobatics. I mainly fly IMAC so it just spins off onto all my other planes.

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